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/* Sv48 address translation for RV64. */
val walk48 : (vaddr48, AccessType, Privilege, bool, bool, paddr64, nat, bool) -> PTW_Result(paddr64, SV48_PTE) effect {rmem, rreg, escape}
function walk48(vaddr, ac, priv, mxr, do_sum, ptb, level, global) = {
let va = Mk_SV48_Vaddr(vaddr);
let pt_ofs : paddr64 = shiftl(EXTZ(shiftr(va.VPNi(), (level * SV48_LEVEL_BITS))[(SV48_LEVEL_BITS - 1) .. 0]),
PTE48_LOG_SIZE);
let pte_addr = ptb + pt_ofs;
match (mem_read(ac, EXTZ(pte_addr), 8, false, false, false)) {
MemException(_) => {
/* print("walk48(vaddr=" ^ BitStr(vaddr) ^ " level=" ^ string_of_int(level)
^ " pt_base=" ^ BitStr(ptb)
^ " pt_ofs=" ^ BitStr(pt_ofs)
^ " pte_addr=" ^ BitStr(pte_addr)
^ ": invalid pte address"); */
PTW_Failure(PTW_Access)
},
MemValue(v) => {
let pte = Mk_SV48_PTE(v);
let pbits = pte.BITS();
let pattr = Mk_PTE_Bits(pbits);
let is_global = global | (pattr.G() == true);
/* print("walk48(vaddr=" ^ BitStr(vaddr) ^ " level=" ^ string_of_int(level)
^ " pt_base=" ^ BitStr(ptb)
^ " pt_ofs=" ^ BitStr(pt_ofs)
^ " pte_addr=" ^ BitStr(pte_addr)
^ " pte=" ^ BitStr(v)); */
if isInvalidPTE(pbits) then {
/* print("walk48: invalid pte"); */
PTW_Failure(PTW_Invalid_PTE)
} else {
if isPTEPtr(pbits) then {
if level == 0 then {
/* last-level PTE contains a pointer instead of a leaf */
/* print("walk48: last-level pte contains a ptr"); */
PTW_Failure(PTW_Invalid_PTE)
} else {
/* walk down the pointer to the next level */
walk48(vaddr, ac, priv, mxr, do_sum, shiftl(EXTZ(pte.PPNi()), PAGESIZE_BITS), level - 1, is_global)
}
} else { /* leaf PTE */
if ~ (checkPTEPermission(ac, priv, mxr, do_sum, pattr)) then {
/* print("walk48: pte permission check failure"); */
PTW_Failure(PTW_No_Permission)
} else {
if level > 0 then { /* superpage */
/* fixme hack: to get a mask of appropriate size */
let mask = shiftl(pte.PPNi() ^ pte.PPNi() ^ EXTZ(0b1), level * SV48_LEVEL_BITS) - 1;
if (pte.PPNi() & mask) != EXTZ(0b0) then {
/* misaligned superpage mapping */
/* print("walk48: misaligned superpage mapping"); */
PTW_Failure(PTW_Misaligned)
} else {
/* add the appropriate bits of the VPN to the superpage PPN */
let ppn = pte.PPNi() | (EXTZ(va.VPNi()) & mask);
/* let res = append(ppn, va.PgOfs());
print("walk48: using superpage: pte.ppn=" ^ BitStr(pte.PPNi())
^ " ppn=" ^ BitStr(ppn) ^ " res=" ^ BitStr(res)); */
PTW_Success(append(ppn, va.PgOfs()), pte, pte_addr, level, is_global)
}
} else {
/* normal leaf PTE */
/* let res = append(pte.PPNi(), va.PgOfs());
print("walk48: pte.ppn=" ^ BitStr(pte.PPNi()) ^ " ppn=" ^ BitStr(pte.PPNi()) ^ " res=" ^ BitStr(res)); */
PTW_Success(append(pte.PPNi(), va.PgOfs()), pte, pte_addr, level, is_global)
}
}
}
}
}
}
}
/* TLB management: single entry for now */
// ideally we would use the below form:
// type TLB48_Entry = TLB_Entry(sizeof(asid64), sizeof(vaddr48), sizeof(paddr64), sizeof(pte64))
type TLB48_Entry = TLB_Entry(16, 48, 56, 64)
register tlb48 : option(TLB48_Entry)
val lookup_TLB48 : (asid64, vaddr48) -> option((nat, TLB48_Entry)) effect {rreg}
function lookup_TLB48(asid, vaddr) =
match tlb48 {
None() => None(),
Some(e) => if match_TLB_Entry(e, asid, vaddr) then Some((0, e)) else None()
}
val add_to_TLB48 : (asid64, vaddr48, paddr64, SV48_PTE, paddr64, nat, bool) -> unit effect {wreg, rreg}
function add_to_TLB48(asid, vAddr, pAddr, pte, pteAddr, level, global) = {
let ent : TLB48_Entry = make_TLB_Entry(asid, global, vAddr, pAddr, pte.bits(), level, pteAddr, SV48_LEVEL_BITS);
tlb48 = Some(ent)
}
function write_TLB48(idx : nat, ent : TLB48_Entry) -> unit =
tlb48 = Some(ent)
val flush_TLB48 : (option(asid64), option(vaddr48)) -> unit effect {rreg, wreg}
function flush_TLB48(asid, addr) =
match (tlb48) {
None() => (),
Some(e) => if flush_TLB_Entry(e, asid, addr)
then tlb48 = None()
else ()
}
/* address translation */
val translate48 : (asid64, paddr64, vaddr48, AccessType, Privilege, bool, bool, nat) -> TR_Result(paddr64, PTW_Error) effect {rreg, wreg, wmv, wmvt, escape, rmem}
function translate48(asid, ptb, vAddr, ac, priv, mxr, do_sum, level) = {
match walk48(vAddr, ac, priv, mxr, do_sum, ptb, level, false) {
PTW_Failure(f) => TR_Failure(f),
PTW_Success(pAddr, pte, pteAddr, level, global) => {
match update_PTE_Bits(Mk_PTE_Bits(pte.BITS()), ac) {
None() => {
add_to_TLB48(asid, vAddr, pAddr, pte, pteAddr, level, global);
TR_Address(pAddr)
},
Some(pbits) =>
if ~ (plat_enable_dirty_update ())
then {
/* pte needs dirty/accessed update but that is not enabled */
TR_Failure(PTW_PTE_Update)
} else {
w_pte : SV48_PTE = update_BITS(pte, pbits.bits());
match mem_write_value(EXTZ(pteAddr), 8, w_pte.bits(), false, false, false) {
MemValue(_) => {
add_to_TLB48(asid, vAddr, pAddr, w_pte, pteAddr, level, global);
TR_Address(pAddr)
},
MemException(e) => {
/* pte is not in valid memory */
TR_Failure(PTW_Access)
}
}
}
}
}
}
}
function init_vmem_sv48() -> unit = {
tlb48 = None()
}
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